An ultrasonic diagnosis apparatus which equips a color Doppler mode displays the two-dimensional distributions of velocity, power, and variance based on a Doppler signal concerning a moving target such as a blood flow. This apparatus can also display a three-dimensional blood flow image or blood flow information at an arbitrary cross-sectional position.
When visualizing a pulsating blood flow in, e.g., a heart or artery, its cycle is analyzed, and received rasters are rearranged, thereby three-dimensionally displaying the cardiac motion for one heartbeat.
Some recent ultrasonic diagnosis apparatuses can detect the blood flow of a fetus to diagnose the fetal developmental state or fetal diseases. A color Doppler method uses a clutter filter which reduces tissue components (clutter components) of a Doppler signal.
The clutter filter reduces low-frequency components of a doppler signal. Many clutter components are reduced by the clutter filter. However, the clutter filter passes the clutter components of quickly moving tissues together with the blood flow components. The clutter components that have passed through the clutter filter appear as clutter noise which makes it difficult to clearly visualize the blood flow of a fetus or the like.